March 30 (Reuters) - U.S. stocks were set to open higher on Wednesday, a day after comments by Federal Reserve Chair Janet Yellen allayed concerns that the central bank would take an aggressive approach to raising interest rates this year.

Yellen, who made her first remarks since the Fed's meeting earlier this month, said inflation in the United States had not yet reached sustainable levels amid risks posed by uncertainty about China's economy and low oil prices.

Yellen's stance contrasts with recent comments from other policymakers who have voiced support for more than one increase this year.

Global markets cheered Yellen's remarks, which suggested that a rate hike was not immediately on the horizon. The dollar fell more than a percent, while bond prices rallied.

"Yellen's comments allowed investors to breathe a sigh of relief that the Fed will not be raising rates in April," said Sam Stovall, U.S. equity strategist at S&P Global Market Intelligence in New York.

Stovall said the Fed would focus on data to see whether a hike in June would be possible.

Data on Wednesday showed the U.S. private sector added 200,000 jobs in March, more than the 194,000 expected. The report, by payrolls processor ADP, serves as a precursor to the more comprehensive nonfarm payrolls data on Friday.